The present invention relates to a tubular and circular self-sealing composite having at least an innerliner in contiguous relationship with a sealant layer with the resulting composite used in the preparation of tires. More specifically, the present invention relates to a tubular self-sealing composite which is continuously and splicelessly formed, cut, and utilized in the manufacture of tires, for example, radial tires.
Heretofore, tires have been manufactured by utilizing a sealant which is applied to an innerliner portion or to the inner periphery of the tire to prevent loss of air upon puncture as by a nail or other object. One of the conventional practices was to apply the sealant material in a dissolved state as by spraying or coating. Such method required the cleaning of the inner surface of the cured tire and the application of the sealant, both by elaborate and expensive equipment. Upon incorporation of the sealant layer into the tire, the solvent would evaporate and enter the air of the factory and thus create potential health problems as well as create environmental and ecological problems. Also, some of the solvent would remain in the tire and evaporate at a later point in time, for example, in a warehouse or in the trunk of a car.
U.S. Pat. No. 1,488,343 is directed to the manufacture of pneumatic tire casing wherein the plies of the carcass and breaker-strip are conventionally molded under heavy pressure; buckling is avoided.
U.S. Pat. No. 3,372,078 is directed to the lamination of at least two layers, each layer having a different cure system. When the two layers are brought together under mild heat treatment, the ingredients comingle at the interface and result in a partial cure.
U.S. Pat. No. 3,933,566 teaches the partial cure or precure of multilayer tire innerliners via radiation to increase green strength.
It is noted that none of these patents teach or suggest a spliceless, tubular innerliner composite, or method for making same.
U.S. Pat. No. 4,140,167 to the same inventor as herein, eliminated the solvent-sealant application by utilizing a sealant which was at least partially degraded by irradiation or heat in the presence of a peroxide. The sealant was in the form of a blend or a laminate and was made and applied in the form of a sheet or strip. The blend or some of the layers of the laminate contained various chemical agents, which either assist or retard cure by irradiation so that the blend or the layers had different physical characteristics during the manufacture of the end products containing the laminate. Thus, the sealant would be initially tough during the initial building state and then the sealant or a portion of the laminate could be degraded by irradiation and form a soft pliable layer as the sealant. Moreover, the sealant still had to be spliced. As known to those skilled in the art, during expansion of the tire building drum, a spliced tire would open up if the spliced adhesion was poor. It is noted that although a coextrusion process could be utilized, it only related to the preparation of strips and not to spliceless, tubular, and circular innerliner composites.